Combine harvesters or combines are equipped with removable heads or “headers” that are designed for harvesting particular types of crops. A “platform header” is typically used for cereal grains such as soybeans and various cereal crops such as wheat, oats and barley. A platform header is equipped with a reciprocating knife cutter bar and has a revolving reel which forces the cut crop into the header as the combine advances. A cross auger forces the cut grain into the feeder house of the combine where the grain is threshed and separated from the cut stalk and other crop chaff “Draper headers” are similar to platform headers in that they utilize a reciprocating cutter bar and a revolving reel. However, instead of a cross auger, the draper header uses a fabric or rubber apron to feed the cut grain into the feeder house. Headers for row crops, particularly corn headers, are equipped with forwardly extending conical snouts which extend between the corn rows. Where adjacent snouts of the corn header converge, instead of cutting the stalk like a platform or draper header, adjacent stalk rollers pinch and pull the stalk downwardly stripping the corn ear from the stalk, so that the stalks pass under the header leaving primarily only the ear and husk enter the feeder house.
When combining or harvesting different crops using any of the foregoing types of headers, the header is typically operated at a height sufficiently low to the ground to ensure that the lowermost grain across the width of the header is not missed. As the crop varies in height or as the terrain varies across the field, the combine operator must adjust the height of the header up or down to ensure that the lowermost grain is not missed while also ensuring that no portion of the header runs aground.
Platform and draper headers can extend up to forty or more feet in width. Accordingly, to account for variations in terrain across the width of the header, especially for harvesting soybeans and other crops that have pods close to the ground, flexible platform and draper headers have been developed which utilize a cutter bar that flexes to better follow the contours of the terrain. However, heretofore, no such “flexible” header has yet been developed for row crops, particularly corn headers. With advances in combine technology, twelve and sixteen row corn headers have become common place and even twenty four row headers are now available. As a result, with corn headers now approaching the widths of platform and draper headers, there is now a need for corn headers to flex, bend or articulate so as to more closely follow the contours of the terrain to avoid missing corn.
For example, referring to FIG. 5, when combining over the crest of a hill with a large header of twelve rows or more, it may not be possible to lower the header sufficiently to avoid missing ears at the far ends of the header without running the header aground at the middle of the header. Likewise, referring to FIG. 6, when combining in a trough or valley between hills, it may not be possible to lower the header sufficiently to avoid missing ears in the middle of the header without running the header aground on the upwardly sloping hills at the far ends of the header.
While lateral tilt headers serve their intended purposes for operating on relatively uniform or consistent grades, the ability of the header to tilt laterally from side-to-side is not much more beneficial than a conventional fixed or non-titling header for harvesting on rolling terrain. For example, referring back to FIGS. 5 and 6, it should be appreciated that having the ability to laterally tilt the header to one side or the other will provide little or no benefit when harvesting over the crest of a hill as in FIG. 5 or in a valley as in FIG. 6. Similarly, referring to FIGS. 7 and 8, when combining along the base of a hill, even when the header is tilted laterally and in the lower most position without running the header aground at the far ends, the ears in the corn rows in the middle of the header may still be missed.
Accordingly, for harvesting row crops on rolling terrain, there is a need for a row crop header, particularly a corn header, that articulates or flexes so that sections of the header can be raised and lowered to more closely follow the terrain to avoid missing rows as the combine traverses the field.